DESCRIPTION (Applicant's abstract): The proposed project is aimed at developing a very inexpensive and rapid diagnostic test that can be used to identify specific infectious organisms. The goal is to make the cost so low that managed health organizations would encourage its regular use in clinical settings, thus greatly reducing prescriptions for antibiotics in cases where they are ineffective, and consequently reducing one source of antimicrobial-resistant strains of bacteria. The proposed diagnostic test is based upon DNA array technology, which can be designed to not only identify infectious pathogens but also determine if antimicrobial resistant bacteria strains are present. The unique feature of the proposed test is that it utilizes an electrical property that is very inexpensive to measure. The test is based on the fact that, under the appropriate conditions, the increase in effective dielectric thickness caused by binding a small amount of DNA to an insulating monolayer on a metal conductor will produce a significant, readily measurable change in measured capacitance. In Phase I, controlled tests are proposed to characterize the new technique and assess its likely effectiveness in a clinical setting. In Phase II, DNA array will be developed to detect common pathogens. PROPOSED COMMERCIAL APPLICATION: A low-cost DNA-based diagnostic test for infectious pathogens could be utilized in essentially every hospital and clinic in the world. As antimicrobial-resistant bacteria become more common, the need for such tests will gain widespread acceptance. We estimate that tens of millions of the arrays will eventually be used each year in U.S. hospitals alone.